Study of evaluation method of wood quality using wavelet transform

Wavelet transform is effective in the processing of an unsteady signal like the tapping tone of the wood. In this study, we try to,develop a method for evaluating wood quality using wavelet transform and the main obtained results can be shown as follows: 1)The Young's modulus calculated by using the resonance frequency obtained from wavelet transform, is compared with one measured. As for both the clear sample and the sample which includes a knot, Young's modulus of the wood can be estimated by finding resonance frequency in wavelet transform. 2)Relation between the degradation of resonance frequency caused by the existence of a knot and the ratio of the knot and the diameter can be approximated in the second polynomial. Therefore, the analysis of the resonance frequencies of clear wood and the wood which includes a knot leads to estimate the amount of knots of the wood.